Treatment of air bags



Patented Aug. 11, 1931 UNETEE STATES PATENT OFFICE CORNELIS VAN annnns, on AKRON, HI-o,-l ssIe 1\TonTo THE. GOODYEAR mna RUBBER CGMLPANY, or AKRON, euro, e.- ooaronaTlon -or onro V TREATMENT or Air. Bees No Drawing.

effects of air and oxygen.

More specifically, my invention has for one of its objects the provision of a relatively vlscous inert glycerme solutlon which, when introduced into an airbag, Wlll form a per- U nianent coating over the interior surface thereof which'will preserve the latter from oxidatlon.

The interior surfaces of airbags or pneubreak readily, thus destroying the usefulness of the bag, and often resulting in lnjury to the tire casings in which they are used.

Heretofore, it has been customary to introduce glycerine into the bags from time to time in order to form a protective coating over the interior surfaces thereof. Glycerine, however, especially when hot, is a relatively 26 thin fluid, which tends to collect in the portions of the airbags that are lowermost and leave the other portions of the surfaces unprotected. This is particularly true when the glycerine solution is first introduced into 39 the bag.

I have discovered that by introducing an inert filler into the glycerine solution the viscosity of the latter may be so increased that when distributed over the interior of the bag it adheres to the surfaces and does not tend to collect in the lower portions of the bag. There are numerous substances adapted to be employed for this purpose. A preferred solution may be obtained by interi mixing glycerine with an emulsifying agent,

a stabilizing ingredient and a drying oil. These materials, when properly mixed, form a stable emulsion which, due to the drying oil, quickly absorbs oxygen and becomes so thick and viscous that it remains permanently part of glue and one and one-half parts of the bagseither before or after they are eared. It ispre'fera lale-,' however, toinject it prior to curing. *Itth'en forms a proteet-i-ag coat- Application filed December 10, 1927'. Serial No. 239,123.

water, Also prepare a 16 percent soap solution, preferably Ivory soap. Intermix one volume of the glue dispersion witho'ne volu-me' offgl'y'c'erine and .2 volume off-the so'a'p 'solution. Heat these materials and'then add-one volume of a drying oil, such as rape seed oil, linseed oil or cotton seed oil to this solution, at the sametime vigorously agitating the mixture. 7 The solution should be inj'e'ctedi'nt'o t'liebags while it is hot, 'a-nd the bagsshou'ld be r'otat'ed'i'n order to distribute this solution over the interior thereof'befoie it has time to become viscous.- matic cores employed in the vulcanization of tires, if unprotected, tend to oxidize and become hard and brittle so that they crack and I The preservative fluid may be injected into ing V within the bag during vulcanization. This methods of treatment permits the use of air as an inflating medium in place of carbon dioxide gas which is usually employed.

This coating material does not become fluid when subjected to the heat of vulcanization and, therefore, it does not tend to flow into the lower portions of the bag.

A satisfactory coating material may also be obtained by extracting the used glycerine from discarded airbags. This material is quite viscous due to the fact that glycerine has a tendency to absorb zinc oxide and other pigments from the rubber which composes the bag itself, and thus it tends to become viscous. The viscous material thus obtained, when injected'into a new airbag, does not readily flow, and hence it forms a permanent coating upon the interior surfaces of the bag. It is also satisfactory as a coating material for the reason that it is already saturated with zinc oxide and other constituents of the rubber itself and so does not absorb those materials from the new bags.

Zinc oxide may also be introduced directly into the glycerine and thus form a protective solution similar to the extracted glycerine just discussed. In this case, pigments should be added until the solution is of proper consistency. Satisfactory results may also be obtained by the employment of pig-. ments other than zinc oxide; for example,

carbon black, talc, barytes, zinc oxide, etc.

It will be apparent from the preceding de scription that I have discovered an improved preservative material adapted to be injected into the interior of airbags. This material is relatively inexpensive and may be prepared with little difficulty. Its use results in a great increase in the life of the airbag. Since the life of an unprotected airbag is relatively short, the latter is an extremely important feature, and results in a very material reduction in the cost incidental to the manufacture of pneumatic tires.

I have disclosed a considerable number of different materials which are adapted to increase the viscosity of a glycerine solution and all of which, when employed for that pur pose, result in a great saving in airbags. It is apparent, therefore, that my invention is of relatively broad scope and includes a wide range of equivalent materials. Therefore, only such limitations should be imposed as are indicated by the appended claim. WhatI claim is:

A method of protecting the interior surfaces of airbags which comprises injecting therein a solution of glycerine extracted from used alrbags.

In witness whereof, I have hereunto signed 7 my name. Y 7 I p Signed at Akron, in the county of Summit 7 and State of Ohio, this'8th day of December 1927. a I p CORNELIS VAN RENNES. 

